Add Warm-Up and Stretching activity types

Adds WorkoutActivityType.warmUp (HealthKit .preparationAndRecovery) and
.stretching (.flexibility), and retags the six starter splits that were all
mislabeled as Functional Strength:

- Warm-Up:    Upper Body Warm-Up, Lower Body Warm-Up, Morning Wake-Up
- Stretching: Morning Mobility, Full Body Stretch, Evening Stretch

The split editor's activity picker surfaces them automatically (CaseIterable).
Older app versions decode the new raw values as the default type — additive and
not schema-gated, so no quarantine.

Exercise Library/Chest Opener/frames/frame-2.svg

@@ -1,13 +1,34 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 180" fill="none">
   <title>Chest Opener</title>
+  <defs>
+    <linearGradient id="grad-leg_l-0" gradientUnits="userSpaceOnUse" x1="164.1" y1="92.3" x2="171.6" y2="123.2"><stop offset="0" stop-color="#515662"/><stop offset="1" stop-color="#a9afba"/></linearGradient>
+    <linearGradient id="grad-leg_r-1" gradientUnits="userSpaceOnUse" x1="165.6" y1="123.9" x2="158.6" y2="150.6"><stop offset="0" stop-color="#3a3f4b"/><stop offset="1" stop-color="#5c616d"/></linearGradient>
+    <linearGradient id="grad-leg_r-2" gradientUnits="userSpaceOnUse" x1="158.6" y1="150.6" x2="166.1" y2="152.5"><stop offset="0" stop-color="#5c616d"/><stop offset="1" stop-color="#626873"/></linearGradient>
+    <linearGradient id="grad-arm_l-0" gradientUnits="userSpaceOnUse" x1="150.8" y1="34.8" x2="147.0" y2="55.2"><stop offset="0" stop-color="#7fccc2"/><stop offset="1" stop-color="#86cfc5"/></linearGradient>
+    <linearGradient id="grad-arm_r-1" gradientUnits="userSpaceOnUse" x1="145.1" y1="56.7" x2="153.0" y2="75.9"><stop offset="0" stop-color="#0d9488"/><stop offset="1" stop-color="#13978b"/></linearGradient>
+  </defs>
   <path d="M 124.9 157.5 L 180.0 157.5 L 180.0 150.2 L 124.9 150.2 Z" fill="none" stroke="#b9bec9" stroke-width="2.1" stroke-linejoin="round"/>
-  <path id="leg_l" d="M 164.1 92.3 L 171.6 123.2 L 161.4 148.9 L 168.6 151.6" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="leg_r" d="M 160.0 92.7 L 165.6 123.9 L 158.6 150.6 L 166.1 152.5" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_l" d="M 150.8 34.8 L 147.0 55.2 L 155.8 73.9" stroke="#86cfc5" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="leg_l">
+    <path d="M 164.1 92.3 L 171.6 123.2" stroke="url(#grad-leg_l-0)" stroke-width="3.77719" stroke-linecap="round"/>
+    <path d="M 171.6 123.2 L 161.4 148.9" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round"/>
+    <path d="M 161.4 148.9 L 168.6 151.6" stroke="#a9afba" stroke-width="3.5" stroke-linecap="round"/>
+  </g>
+  <g id="leg_r">
+    <path d="M 160.0 92.7 L 165.6 123.9" stroke="#3a3f4b" stroke-width="4.2" stroke-linecap="round"/>
+    <path d="M 165.6 123.9 L 158.6 150.6" stroke="url(#grad-leg_r-1)" stroke-width="4.09338" stroke-linecap="round"/>
+    <path d="M 158.6 150.6 L 166.1 152.5" stroke="url(#grad-leg_r-2)" stroke-width="3.96643" stroke-linecap="round"/>
+  </g>
+  <g id="arm_l">
+    <path d="M 150.8 34.8 L 147.0 55.2" stroke="url(#grad-arm_l-0)" stroke-width="3.51883" stroke-linecap="round"/>
+    <path d="M 147.0 55.2 L 155.8 73.9" stroke="#86cfc5" stroke-width="3.5" stroke-linecap="round"/>
+  </g>
   <path id="girdle" d="M 150.8 34.8 L 146.7 34.8 L 146.7 36.1" stroke="#0d9488" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="pelvisBar" d="M 164.1 92.3 L 160.0 91.8 L 160.0 92.7" stroke="#0d9488" stroke-width="3.5" stroke-linecap="round" stroke-linejoin="round"/>
   <path id="spine" d="M 160.0 91.8 Q 156.2 61.9 146.7 34.8" stroke="#0d9488" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
-  <path id="arm_r" d="M 146.7 36.1 L 145.1 56.7 L 153.0 75.9" stroke="#0d9488" stroke-width="4.2" stroke-linecap="round" stroke-linejoin="round"/>
+  <g id="arm_r">
+    <path d="M 146.7 36.1 L 145.1 56.7" stroke="#0d9488" stroke-width="4.2" stroke-linecap="round"/>
+    <path d="M 145.1 56.7 L 153.0 75.9" stroke="url(#grad-arm_r-1)" stroke-width="4.18231" stroke-linecap="round"/>
+  </g>
   <circle id="head" cx="140.3" cy="22.5" r="7.0" fill="white" stroke="#3a3f4b" stroke-width="4.2"/>
   <line id="nose" x1="145.6" y1="17.8" x2="149.2" y2="14.6" stroke="#3a3f4b" stroke-width="2.8" stroke-linecap="round"/>
   <g font-family="-apple-system, Helvetica, sans-serif" font-size="11" fill="#6b7180">